Conventionally, scattered-light methods are used to measure the concentration of particles in exhaust gases and other colloids.
It is usual to use in this context a high-intensity light source, for example a laser, that radiates light into a measurement chamber through which the colloid to be measured is being guided. At least one light sensor, which detects light that has been scattered from particles present in the colloid, is present. In order to check for proper functionality of a scattered-light measuring device of this kind, and to calibrate the device, it is necessary to establish in the measurement chamber a defined state in which the irradiated light is scattered in a defined and known manner. Scattered-light measuring devices that are used for official measurements are subject to a calibration requirement, further increasing the need to supply accurate and highly reliable measurement results.